This disclosure relates to Japanese Application Hei 11 306639, which is incorporated by reference herein and from which priority is claimed.
The present invention relates to an electronic musical instrument and, in particular, to an electronic musical instrument that has an accompaniment capability.
For some time, electronic musical instruments have included accompaniment capabilities such that, at the time that a performer renders a performance by, for example, operating the keys of a keyboard, an accompaniment is played by the electronic musical instrument with a composition that accompanies the main composition that is being performed by the performer. With this type of electronic musical instrument, it is possible for the performer to enjoy an accompanied performance, accompanied by the composition that has been supplied by the electronic musical instrument. In addition, with prior electronic musical instruments, the performer can adjust the performance tempo of the accompanying composition, for example, by operating such things as a dial used for tempo adjustment. The performer can then perform the main composition while matching the accompanying composition by adjusting the tempo of the accompanying composition.
However, when the performer originally performs the main composition, he or she performs it at a free tempo that is in accord with his or her own feelings. Despite the fact that the accompanying composition should be made to accompany the performance by the performer, that is, matching the performance tempo of the main composition, there has been a problem with prior art electronic musical instruments in that if the performer performs at a free tempo in accord with his or her own feelings at the time of the performance, the tempo of the accompaniment will be off. In addition, there are cases where the performer desires to perform, and change the performance tempo in the middle of the composition. With the prior art electronic musical instruments, in order to match the performance tempo, the tempo of the accompaniment must be adjusted if the performer changes tempo in the middle of a composition. In addition to changing the performance tempo in the middle of the composition, the performer must carry out the performance of the main composition while operating such things as a dial for adjusting the tempo of the accompaniment. Attempting to match the tempo of the accompaniment to the performance can thus prove troublesome.
Accordingly, to overcome limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading the present specification, preferred embodiments of the present invention relate to an electronic musical instrument with which it is possible to have an accompaniment that tracks the performance tempo of the performer. Preferred embodiments of the present invention relate to methods and apparatus for taking into consideration the difficulties in matching a performance of a musical piece by an artist with an electronically provided accompaniment.
A preferred embodiment of the present system comprises an electronic musical instrument that adjusts the tempo of an accompaniment to track the performance tempo of the performer. In particular, preferred embodiments of the present system provide a method for receiving performance data in which a multiple number of performance data characteristics are received and analyzed in accordance with the progression of a performance of a composition by a musician.
In particular preferred embodiments of the present invention provide a storage means in which a sequence of performance data, which characterizes a specific performance composition is stored.
Preferred embodiments also contain a retrieval means in which, from the sequence of performance data that has been stored within the storage means, segments that correspond to the multiple sequences of performance data, which has been continuously received when the storage means are retrieved.
Preferred embodiments also comprise a tempo calculation means. The tempo calculation means can perform a comparison between the stored performance data segments and the data that is being continually received by the performance data reception means. By means of a comparison between the performance data, with which the segments of data have been found in the previously mentioned retrieval means and the multiple number of performance data that have been continuously received by the aforementioned performance data reception means, the relative performance tempos of the multiple number of performance data that have been continuously received by said performance data reception means are calculated with respect to the performance tempo in the segments and in accompaniment means in which an accompaniment is done at a performance tempo that corresponds to the relative performance tempos that have been calculated by the previously mentioned tempo calculation means. In other words, the tempo calculation means can compare the performance as received with a performance as stored in memory. By knowing the relative performance tempos of the stored performance and the received performance the embodiment can adjust the tempo of the accompaniment.
In an exemplary embodiment, performance data reception means may be one that is primarily composed of the keyboard, wherein the performer performs by operating the keyboard, etc. and receives the performance data that expresses each performance operation at the time of the performance of the operation. In other embodiments, the performance data reception may be one in which the MIDI data, etc. of the composition is provided by such things as a Musical Instrument Digital Interface port, and is received in real time in accordance with the reproduction of the composition.
In accordance with embodiments of electronic musical instrument used with the present invention, the relative performance tempo of the performance and operation by the performer is calculated using the performance tempo of the main composition that has been stored in advance it the storage means as the standard. The accompaniment is done at a performance tempo that is in accord with the relative performance tempo of the main composition. Accordingly, when the tempo of the performance by the performer is fast, the tempo of the accompaniment is also fast. When the tempo of the performance by the performer is slow, the tempo of the accompaniment is also slow. That is to say, the accompaniment is done by tracking the tempo of the performance of the performer.
With electronic musical instruments embodied by the present invention, the above mentioned retrieval means may be one in which a segment that corresponds to a specified amount of performance data that have been received by the performance data reception means from a sequence of performance data that are stored in the storage means is retrieved. The above mentioned retrieval means may also be one in which a segment that corresponds to a multiple number of performance data that had been recently received in a specified time period by the performance data reception means from a sequence of performance data that are stored in the storage means is retrieved.
In somewhat more general terms, the tempo may be calculated depending upon a specific amount of performance which is received, or the tempo may be calculated by observing how much of a performance is received during a specific amount of time.
With the format in which the performance tempo is calculated based on a specific amount of performance data that has been recently received, the responsiveness of the system is good. This is, in general, because the performance data of the accompaniment tracks at the time that the performer carries out the performance.
In addition, there are cases where the number of times that the performance calculation should be carried out per beat changes greatly within a single composition. In such a case, there are times when the performer performs conscious of the tempo of one beat or several beats despite the number of performance calculation operations. Using the format in which a performance tempo is calculated based on the performance data that have recently been received in a specific time, since this kind of performance tempo for one beat (or for several beats) is calculated, it is possible to have an accompaniment at a tempo that is close to the performance tempo of which the performer is conscious.
In addition, in embodiments of musical instruments of the present invention, the aforementioned tempo calculation means may be one that calculates the mean value of the ratio between each interperformance data time interval in the above mentioned segments and each of the multiple number of interperformance data time intervals that have been received continuously by the performance data reception means that correspond to the segments as the relative performance tempo of the number of performance data that have been received continuously by the performance data reception means with respect to the performance tempos in the segments. The aforementioned tempo calculation means may also be one that calculates the ratio between the total performance time in the above mentioned segments and the total performance time of the multiple number of performance data that have been received continuously by the performance data reception means that correspond to the segments as the relative performance tempo of the multiple number of performance data that have been received continuously by the performance data reception means with respect to the performance tempos in the segments.
In other words, embodiments of the present invention within a musical instrument may reference the tempo in the piece of music being performed to the tempo of the stored reference performance in two different ways. The stored reference performance has a tempo which is known. In addition, the relationship between the tempo of the stored reference performance and the stored accompaniment is known. By knowing a ratio between the tempo of the live performance and the stored reference performance, a ratio can be formed. The ratio can then be used to produce the accompaniment in the correct tempo. The first method of calculating the ratio between the tempo of the live performance and the stored reference performance is to calculate the data time interval of a given segment of the performance. For example, the time that it would take to play the first 15 notes in the actual performance can be determined and compared to the time that it takes to perform 15 notes in the stored reference performance. By knowing the time that it takes to perform the same interval of music in the reference and the actual performance, a tempo ratio can be performed. Several tempo ratios can be formed for the ratio between the tempo and the performed piece and the stored reference performance. These tempo ratios may be then averaged to ascertain a mean value representing the difference in the tempos of the performed work and the stored reference work. Since the stored reference work and the performed work are the same pieces of music, the tempo ratios can be used to speed up or slow down the accompaniment. A mean value of the tempo ratios between the performed and the reference piece may be found. The main values may not be limited to simply an arithmetic mean value but may form weighted mean values or geometrical mean values.
A second way to calculate the tempo of a performed piece of music is as follows: once again the tempo in the performed piece of music will be compared with the tempo in a reference piece which is stored within the instrument. As before, the accompaniment is also stored. The accompaniment is referenced to the stored piece. By forming a ratio of the tempo between the performed piece and the stored reference piece, the difference between the tempo of the performed piece and the reference piece can be determined. This ratio of tempos between the performed piece and the stored piece can then be used to speed up or slow down the tempo of the accompaniment.
In the second method that calculates the ratio of the tempo of the performed piece to the stored reference piece, instead of looking at the time interval that a particular piece of musical data takes, the method ascertains how much data is input within a particular time interval.
With the format in which the mean value of the ratio of the interperformance data time intervals is used as performance tempo, the performer uses a performance tempo at the time of carrying out each performance operation that is suitable to the type of composition of which he or she is conscious and to the performance method; and, with the format in which the ratio of the total performance time of the performance data is used as the performance tempo, the performer uses a performance tempo that is suitable to the composition of which he or she is conscious and to the performance method with, for example, only the beginning of a bar.